This invention relates to an endoscope having a plurality of observation optical systems, and more particularly to an endoscope having a plurality of optical systems each provided with an identification mark element which lies in view of an ocular section of the endoscope while the optical system is used.
An endoscope has been known which is provided with two or more optical systems, for example, a front viewing optical system and a lateral viewing optical system so as to be selectively used. When one of them is used, its proximal end faces the ocular section of the endoscope. Since the proximal ends of the optical systems, which appear in the field of view of the ocular section, are identical and can hardly be distinguished from one another, an operator must previously ascertain which optical system is used. When the operator forgets during the observation of a body cavity which observation optical system is actually used, or it has become impossible to judge which optical system is used at the present moment due to their repeated interchanges, the difficulties arise in operating the endoscope safely and reliably.